The present invention provides novel advanced epoxy resin compositions containing triazine or both triazine and oxazoline groups, as well as cured compositions prepared from said epoxy resins.
Epoxy resins are the reaction product of a diphenol or polyphenol with an epihalohydrin and a basic-acting material. Said reaction generally involves two distinct steps: coupling reaction of the epihalohydrin and diphenol or polyphenol to provide a halohydrin intermediate and dehydrohalogenation reaction of the halohydrin intermediate to provide the glycidyl ether product.
It is known, for example, as taught by Bender et al. in U.S. Pat. No. 2,506,486 that epoxy resins can be reacted with diphenols. Said reaction involves etherification of hydroxyl groups via reaction with epoxide groups. This reaction is designated as an advancement reaction and the product thereof is an advanced epoxy resin.
Preparation of polyepoxides containing triazine groups is taught by R. E. Hefner, Jr. in Application Ser. No. 547,537 filed Oct. 3, 1983. The process disclosed therein uses an easily prepared mixed cyanate of a diphenol or polyphenol. More specifically, the process disclosed comprises reacting at least one material having an average of more than one aromatic hydroxyl group per molecule with at least 0.01 but not more than 0.95 moles of cyanogen halide or mixture of cyanogen halides per aromatic hydroxyl group in the presence of a suitable base in a quantity of from about 0.01 to about 1.1 moles per aromatic hydroxyl group at a temperature and time sufficient to essentially complete the reaction and thereafter recovering the resultant cyanate mixture; trimerizing the resultant cyanate mixture in the presence of a suitable trimerization catalyst at a temperature and time to essentially complete the trimerization reaction; epoxidizing the resultant trimerized product in a conventional manner by reaction with an epihalohydrin with subsequent dehydrohalogenation with a basic-acting material and finally recovering the resultant triazine functional glycidyl ether product. Excellent control over the molecular weight and content of triazone groups is provided by this process. The resultant epoxy resin compositions possess unusually high thermal stability as well as excellent overall physical and mechanical properties.
Preparation of polyepoxides containing triazine and oxazoline groups is taught by R.E.Hefner, Jr. in patent application Ser. No. 576304 filed 2/2/84. The process disclosed therein uses the aforementioned mixed cyanate of a diphenol or polyphenol. Co-oligomerization of this cyanate mixture with an epoxy resin, such as a diglycidyl either of bisphenol A, provides hydroxyaromatic oligomers both triazine and oxazoline groups. Oligomers prepared from co-oligomerization of the mixed cyanate of a diphenol with an epoxy resin using mole ratios of epoxy groups to nitrile groups of about 1 to 10 about 1 to 40 or more are disclosed for the process described. The oligomers, and unreacted diphenol, if any, are then epoxidized using methods well known in the art. The resultant epoxy resin compositions posses excellent thermal stability as well as enhanced mechanical properties.
The advanced epoxy resin compositions of the present invention contain triazine groups or both triazine and oxazoline groups and are derived by reaction of the respective triazine-containing or triazine-containing and oxazoline-containing hydroxyaromatic oligomers with an epoxy resin. The invention consists of the advanced epoxy resins as well as cured compositions thereof.